The present invention relates to an absorbent article including wing-shaped flaps wrapped around the crotch of an undergarment when fixed to the undergarment.
For example, as shown in FIGS. 15 and 16, a conventional absorptive article N, e.g., a sanitary napkin, a pantiliner, a pad for vaginal discharge, and an incontinence pad is known. The absorptive article N contains an absorbing body 52 made of a cotton-state pulp between an impermeable back-surface sheet 50 such as a polyethylene sheet and a polyethylene laminate unwoven cloth and a permeable front-surface sheet 51 such as a nonwoven cloth and a permeable plastic sheet.
In order to fix the absorbent article N of this type in an attached state, the absorbent article N includes at least one adhesive layer 53 formed on, for example, the skin non-contact surface (outer surface) of the absorbent article N, wing-shaped flaps W integrally formed on both sides of a napkin body in the longitudinal direction so as to extend to the outside, and adhesive layers 54 provided on the surface of the impermeable back-surface sheet 50 side of the wing-shaped flaps W (outer surfaces).
When the absorbent article N is fixed to an undergarment 30, as illustrated in FIG. 17, the absorbent article N is fit to the crotch of the undergarment. The laterally extending wing-shaped flaps W are drawn from the undergarment. The wing-shaped flaps W are folded at folding lines RL and then are bonded to the outer surface of the crotch of the undergarment 30 to wrap around the crotch of the undergarment.
For individual packaging of the absorbent articles N, the absorbent article N may be packed in a first pattern (see Japanese Patent Laid Open No. 9-94267) in which the wing-shaped flaps W are folded to the unused surface (back surface) of the absorbent article N (hereinafter, may be simply called backward folding) or the absorbent article N may be packed in a second pattern (see Japanese Patent No. 3163233) as shown in FIG. 18 in which the wing-shaped flaps W are folded to the use surface (front side) of the absorbent article N (hereinafter, may be simply called front folding) so as to cover the respective adhesive layers 54 and the wing-shaped flaps W are connected through release paper 56 extending over the adhesive layers 54.
In the individual packaging of the first pattern, however, when a package is opened and the release paper is removed to attach the absorbent article N to the undergarment, the wing-shaped flaps W need to be unfolded by hand because the wing-shaped flaps W have been folded to the back side. In some cases, the adhesive layers 54 of the wing-shaped flaps W may be bonded to the back sheet 50 of the body and thus the peeling of the adhesive layers 54 may stretch or break the base material of the back sheet 50 of the body, so that the napkin may become unusable.
In the individual packaging of the second pattern, the wing-shaped flaps W have been folded to the use surface and thus the adhesive layers 54 formed on the wing-shaped flaps W are not bonded to the adhesive layers 53 formed on the back surface of the body. However, the release paper 56 extended over the wing-shaped flaps W needs to be separately peeled off and discarded by hand, so that one-step opening (release paper is automatically removed by a single opening operation) is not achieved. Even when the release paper 56 is peeled off, the wing-shaped flaps W are not automatically unfolded and remain folded to the front surface side by the folding line. Thus, a user needs to unfold the wing-shaped flaps W by hand upon attachment, requiring a long time for attachment.
To address this problem, the present applicant has proposed a napkin in Japanese Patent Laid Open No. 2004-113590. As illustrated in FIG. 19, the napkin in a packaged state includes a wing release material 59 covering the fixing adhesive layers 54 formed on the wing-shaped flaps W. The wing-shaped flaps W are folded to the permeable front-surface sheet side along with the wing release material 59, the wing release material 59 is extended to the surface of the impermeable back-surface sheet 50 over the folding line positions of the wing-shaped flaps W, and the wing release material 59 on the surface of the impermeable back-surface sheet 50 is fixed to a packaging material directly or through a body release material covering the fixing adhesive layers. In a state in which the wing-shaped flaps W are folded to the permeable front-surface sheet side along with the wing release material 59, the ends of the wing-shaped flaps W overlap each other so as to temporarily fix the wing-shaped flaps W to each other. Furthermore, the present inventor has proposed a napkin in Japanese Patent Laid Open No. 2008-136566 in which the adhesive strength of a wing-temporarily-fixing adhesive layer that joins the wing-shaped flaps is set lower than that of the wing-fixing adhesive layer and the wing release material.